User manual

Wide Bank 28 DS3 - Release 2.4 July 2004 7-17
Diagnostics & Troubleshooting
Looptests Using Built-in PRBS BERT
DS3 Loopup Network with PRBS BERT
This test sends a high-speed NIU loop code and unframed PRBS test pattern toward the far-end,
which can be another Wide Bank or other NIU device. The far-end device loops back the high-speed
signal to the near-end Wide Bank. The returned high-speed signal is analyzed by the built-in Bit
Error Rate Tester (BERT) and the PRBS error rate is displayed in the hour statistics.
NOTE: When ds3 protect is turned on, the ds3 send command will transmit codes over
both primary and secondary DS3s.
1. Configure for DS3 network loopback and PRBS test.
(A:Active)> ds3 send loopup
(A:Active)> ds3 send prbs
2. Verify that PRBS SYNC SEC is incrementing.
(A:Active)> hour ds3
3. When finished, disable loopback and PRBS test.
(A:Active)> ds3 send off(A:Active)> ds3 send loopdown
Figure 7-7 DS3 Network Looptest with PRBS BERT
Trans-
ceiver
Selector
M13
Framer
Trans-
ceiver
Relays
LS Card HS Card
Send AIS
Trans-
ceiver
Selector
M13
Framer
Trans-
ceiver
Relays
LS Card HS Card
Toward DS1/E1
DS3
DS3
Send DS3 Loopup
Send PRBS
Toward DS3
Loop Detect
Must be Enabled
Relays
DS1/E1
DS1/E1
Local LS
Far-End LS
Relays
Near-End (Local) DS3
Far-End DS3
Send AIS
Toward DS1/E1
Wide Bank or Other NIU